Is Seasonal Affective Disorder Real? This Study Casts Some Doubt On Its Existence

It's getting to be the time of year when we all wish we could lay in bed until spring comes around. Most of us experience the winter blues at some point, but is seasonal affective disorder "real," so to speak? According to a large-scale study published in the journal Clinical Psychological Science, the disorder may be less common than previously thought — and, in fact, the study questions its existence as a unique disorder in the first place.

Part of the problem lies in the criteria for seasonal affective disorder (SAD): Characterized as a seasonal variation of major depression, diagnosis requires patients to report recurring episodes of depression that coincide with specific seasons. (Most experience episodes during late fall or winter, but it has been known to occur in summer as well.) However, recent research has questioned the validity of the methods of reporting symptoms, as patients are often asked to recount depressive episodes from the last 12 months or more. Furthermore, a 2011 article pointed out that although research seems to point to the existence of some sort of seasonal depression, the results are so varied that they make drawing conclusions difficult — especially since it's notoriously difficult to discern the role of the placebo effect in the disorder's existence.

In light of this research, scientists at Auburn University in Montgomery decided to look into the existence of SAD as opposed to major depression. Using survey data from more than 34,000 participants, researchers compared participants' depressive symptoms over the past two weeks with season-related information: The date of the survey, amount of sunlight exposure based on geographic location, and so on.

The results of the study showed no link between symptoms of depression and the season, nor did they indicate any seasonality in the depressive episodes experienced by participants who fit the criteria for major depression. In short, people who took the survey in the winter were no more likely to be depressed than those who took it in the summer, even if they showed signs of major depression.

Of course, this doesn't mean that researchers deny the existence of depression during the fall and winter — rather, they question the assumption that seasons are the cause for depression. "Being depressed during winter is not evidence that one is depressed because of winter," researchers wrote, according to Psychological Science. At the very least, they argue that SAD may not be as common as it's assumed to be, which is backed up by previous research indicating that the disorder is overdiagnosed.